It is known to provide gas fireplace inserts that are designed to be retrofitted into wood burning fireplaces. Examples of such inserts are disclosed in U.S. Pat. No. 5,191,877 to Shimek, U.S. Pat. No. 5,752,500 to Jamieson et al., U.S. Pat. No. 6,029,655 to Hussong et al. and U.S. Pat. No. 6,116,232 to Valters et al.
The use and installation of gas fireplace inserts are constrained by certain conditions. Inserts of the sealed combustion type are often provided with an integral heat exchange passageway around the firebox into which room air is drawn in, heated and expelled back into the room. The pathway is defined by an outer wall of the insert that is spaced from the top and back walls of the firebox. Circulation of air through the pathway is often ensured by a blower mounted beneath or to the rear of the firebox. Legs or brackets supporting the firebox base provide a gap under the firebox to accommodate the gas piping and controls (and sometimes a blower) and to define the bottom part of the pathway. Heated air is exhausted forward into the room from the top of the firebox, immediately above the window of the insert.
Gas fireplace inserts should provide an aesthetically pleasing appearance. One means of doing so is to mask the gap between the insert and the inner walls of the hearth of the original fireplace. This is accomplished by providing trim designed to overlap the outer edges of the fireplace mouth (and sometimes the louvers and original fireplace facing). The trim connects to the insert such that the insert window lies generally in the plane of the fireplace mouth.
In order to provide as large a window as possible while still accommodating the outer dimensions of the insert, the insert is made as large as possible while still allowing it to be slid to the back of the hearth. As a result, there is usually very little clearance (sometimes as little as half an inch) between the top of the insert and the bottom of the lintel, baffle or smoke curtain that is provided in many wood burning fireplaces. This tight fit presents challenges to installers who are required to fit ducting or liners from the flue onto the insert's vent connector. In some cases, installers are known to remove the smoke curtain, portions of the masonry wall of the fireplace and the metal floor of manufactured fireplaces in order to install inserts. Such modifications to the fireplace stand the risk of running afoul of building codes and gas appliance restrictions.
Because of the use of trim that extends from the edges of the window of the insert to past the edges of the fireplace mouth, there is often a disproportionate amount of trim in relation to the surface area of the window. This may detract from the appearance of the fireplace by making the window look small in proportion to the overall fireplace. Various approaches are taken to minimize such effect. These include maximizing the size of the window within the constraints mentioned above, as well as providing various decorative elements and treatments to the facing. This “porthole” effect is compounded by the fact that a portion of the front area of the insert is taken up by the outlet of the heat exchange passageway, leaving less space available for the window.
As inserts are seated on the floor inside the hearth with a glass panel in the plane of the fireplace mouth, this constrains how far into the fireplace hearth the insert can be seated. This usually makes the insert look significantly shallower than the original fireplace.
It is an object of the present invention to provide a fireplace insert that offers an improved physical appearance to the installed insert. More particularly it is an object of the invention to provide an insert that looks larger, sits deeper, and is less distinguishable as an insert than the inserts of the prior art.
It is a more particular object of the invention to provide a gas fireplace insert wherein the installed insert creates the illusion of a single appliance set in an open hearth while still providing effective heating and circulation of room air.
It is a further object of the invention to provide a fireplace insert for a wood burning fireplace that is easier to install than prior art inserts, and which is easier to connect the insert vent to flue liners or ducting.
It is yet a further object of the invention to provide airflow around the fireplace insert that minimizes obstructive turbulence near the top of the insert.
These and other objects of the invention will be more fully appreciated by reference to the detailed description that follows. It will be noted that not all objects of the invention are necessarily realized in all possible embodiments of the invention as defined by each claim.